Method of making coreless golf balls



Patented Mar. 10, 1942 Ianalisis oI-EicE METHOD OF MAKING CORELESS GOLF BALLS David George Slevin, Providence, It. I., assigner to United States Rubber Company, New York, N. Y., a corporation of New Jersey Application February 8, 1941, Serial No. 377,960

'(Cl. 154-19) y to the relaxation in tension of the thread all the l5 Claims.

This invention relates to a method of making coreless golf balls.

The invention is an improvement over that disclosed inmy application Serial No. 368,282, tiled December 3, 1940.

For a number of years standard better grade golf balls have been made with a liquid or paste filled center over which is wound a highly tensed rubber thread or tape. This construction is a desirable one, since the fluid center can distort under a heavy blow, but at the same time the highly tensed and hard outer'thread winding produces a .very rapid recovery from the distortion, thus rendering the ball very quick off the club, and giving the desired long distance. The

size and Weight requirements for standard golf way to the outer windings, the latter do not have the desired high tension and hardness.

Finally, thread is deteriorated by the ,addition of the loading material so that it does not have the desired extreme elongation and othergproperties.

In the present invention all of the above diiiiculties are overcome by-winding a tensed and relatively highly loaded thread over a liquid lled center, but limiting the winding to a relatively small diameter. Aiter deflating the center the ball is then wound to the finished diameter ballsl are quite strict, and in order to bring balls of this type up to the required weight it has been necessary to add weighting or loading material, which is usually done by distributing a lilnely divided Weighting material in the liquid iiller. This is objectionable because there is a tendency for the weighting material to separate out from the liquid, thus unbalancing the ball'.

The making of 'a coreless wound golf ball is quite old, in the earlier types this being accomplished by bunching some oi the rubber thread and manually winding the ball until it was of a 'size suiicient to be placed in a winding machine.

This method was objectionable in the time and labor consumed and by reason of the irregular tension and irregular shape caused by hand winding. More recently, coreless halls have been made by directly machine winding the entire ball, but this requires special equipment and cannot be accomplished by the winding mechanism commonly' employed in making `the liquid filled balls.

In my above mentioned application there has been disclosed a method for making a coreless sac can be made in any of the commonly known` `ball 'which requires only the usual equipment employed in making a liquid illledball, and in the said application the thread is weighted to produce the desired finished weight in the ball.

However, this weighted thread extends throughout the whole ball body, While it is desirable that the Weight be more or less concentrated inthe central portion of the ball.` yAlso, when the liquid filled center employed was deflated the tensed rubber thread relaxed, although in diminishing degree, all the way to the outer-.windings and caused a contraction in size of lthe wound ball. It was necessary to overcome this by winding the ball slightly oversize before deflating the center; Another objection to this method is that due with a highly tensed and unloaded thread.

An object of the present invention is to prvide an economical method, not requiring special equipment, for making a coreless golf ball, and invwli'ich the'advantages of the liquid center balls and previous coreless balls are combined.

Another object is to provide an improved and highly eilicient golf ball.

Still further objects will appear from the detailed description and drawing, in which latter: Figure 1 is a section through the liquid iilled center; l

Figure 2 is a similar section through the center after partially winding with a loaded thread and showing an inserted hypodermic needle;

Figure 3 is a section through the wound center oi Figure 2 after the liquid has been withdrawn from the center; and

Figure 4 is a section through a finished ball. Referring to the drawing, there is shown in Figure i a thin-walled sac or container i filled with liquid 2. This sac may be of rubber or any other suitable elastic material and the nlled Ways.` If desired, the sac instead of being filled with liquid may be lled with va solid, easily liquenable material. If iilled with a liquid, it is desirable `to first freeze the container and contents before the winding operation.

The lled container is then wound with the highly tensed and weighted or maded thread s,

as shown in Figure 2. The extent of Winding with the loaded thread may be varied as desired in accordance with the size of center used, the amount of weighting material employed in the thread, and other variables. As an example however the filled center i may be of approximately 1" diameter and wound with the'loaded thread to a diameter of about 1.2. 0n deflation, as described below, the center will be a diameter slightly more than 1".

`lifter completing the winding of the loaded caused to melt, after which a hypodermic needle 4 may be inserted and the liquid 2 withdrawn. As soon as the liquid is withdrawn the pressure of the tensed wound thread causes the collapse of the container yl which in turn permits the thread to relax, this relaxation taking placev in a diminishing. degree all the way to the outer windings. effect of the deflation with the container I collapsed into a small'mass at the center with thethread 3 relaxed to the greatest extent around the container as shown at l'. Due to this relaxationv there is a slight reduction in size of the partially wound ball. Following this the partially wound ball shown in Figure 3 may be inserted in the winding machine again and windings of highly tensed unloaded rubber thread I applied until the nished diameter is reached. The usual form` of cover 6 may then be applied and the ball nishedin the'usual manner.

It will be seen that by the present invention the advantages of the liquid lled center ball and the coreless balls have been combined. The

weighting material used for bringing the ball up to the required weight is concentrated in the central portion, and this central portion is somewhat softer due to the relaxtion of t'ne thread which if desired may also be made of a weightedl rubber, the extent of weighting of the ball can be varied, and this can also be altered by varying the quantity of loaded thread applied or by varying the quantity of loading material used in making it. Also, by varying the size of the container and the quantity of weighted thread applied, the quantity of unweightedv thread for the outer windings will be correspondingly varied, and thus the hardness of the ball can also be altered to suit, which result can also bey varied Iny Figure S'there is illustrated the 1. The steps in making a golf'ball which com- 4 prises winding a tensed, relatively high gravity elastic element arounda collapsible hollow center lled with an easily liqueable solid material,

liquefying said material, hypodermically withdrawing the material to thereby collapse said center and partially relax said wound element, and completing the ball winding with a tensed elastic element of less gravity.

2. The method of making a golf ball which comprises winding a tensed, relatively high gravity and narrow elastic element around an'- elastic hollow center iilled with an easilyliquefiof course by varying the tension used on the unloaded outer thread windings.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

hypodermically withdrawing the material to thereby collapse said center and partially relax said elastic element, completing the ball winding with a tensed elastic element'of less gravity, and applying a cover.

3. The method of making a golf ball which com rises winding a tensed, relatively highly weig ted narrow'rubber element around la collapsible hollow center iilled with an easily liquefiable solid material, liquefying said material,

hypodermically withdrawing the material to thereby collapse said center and partially relz'ix.,4 `said wound element, completing the ball windingA with a tensed rubber thread of less gravity, and applying a cover.

4. The method of making a golf ball which comprises winding a tensed, relatively highly weighted narrow rubber element around a thin' walled hollow rubber center iilled with an easily liqueable solid material, liquefying said material, hypodermically withdrawing the material to thereby collapse `said center and partially relax said wound element, completing the ball winding with a tensed rubber 'thread of less gravity, and applying a cover.

5. The method of making a golf ball which' comprises forming an easily collapsible hollow rubber container iilled with liquid, freezing the I liquid and container in spherical form, winding a highly tensed and relatively highly weighted rub-l ber thread around said container, liquefying the container contents. hypodermically withdrawing vthe liquid to thereby collapse the container and partially relax said thread, completing the ball winding with a highly tensed unweighted rubber thread, and applying a cover. A

DAVID G. SLOVIN. 

